diff --git a/llvm/lib/MC/MCParser/AsmParser.cpp b/llvm/lib/MC/MCParser/AsmParser.cpp
index 7b98e434360f..d0d2a435a52f 100644
--- a/llvm/lib/MC/MCParser/AsmParser.cpp
+++ b/llvm/lib/MC/MCParser/AsmParser.cpp
@@ -3451,10 +3451,14 @@ bool AsmParser::parseDirectiveAlign(bool IsPow2, unsigned ValueSize) {
     // up to one.
     if (Alignment == 0)
       Alignment = 1;
-    if (!isPowerOf2_64(Alignment))
+    else if (!isPowerOf2_64(Alignment)) {
       ReturnVal |= Error(AlignmentLoc, "alignment must be a power of 2");
-    if (!isUInt<32>(Alignment))
+      Alignment = PowerOf2Floor(Alignment);
+    }
+    if (!isUInt<32>(Alignment)) {
       ReturnVal |= Error(AlignmentLoc, "alignment must be smaller than 2**32");
+      Alignment = 1u << 31;
+    }
   }
 
   // Diagnose non-sensical max bytes to align.
diff --git a/llvm/test/MC/AsmParser/directive_align.s b/llvm/test/MC/AsmParser/directive_align.s
index 91148eb635ba..0430f5174086 100644
--- a/llvm/test/MC/AsmParser/directive_align.s
+++ b/llvm/test/MC/AsmParser/directive_align.s
@@ -12,10 +12,25 @@ TEST1:
         .align32 3,,2
 
 # CHECK: TEST2:
-# CHECK: .balign 3, 10
+# CHECK-WARN: error: alignment must be a power of 2
+# CHECK: .p2align 1, 0xa
 TEST2:  
         .balign 3,10
 
 # CHECK-WARN: p2align directive with no operand(s) is ignored
 TEST3:  
         .p2align
+
+# CHECK: TEST4:
+# CHECK: .p2align  31, 0x90
+# CHECK-WARN: error: alignment must be smaller than 2**32
+TEST4:  
+        .balign 0x100000000, 0x90
+
+# CHECK: TEST5:
+# CHECK: .p2align  31, 0x90
+# CHECK-WARN: error: alignment must be a power of 2
+# CHECK-WARN: error: alignment must be smaller than 2**32
+TEST5:  
+        .balign 0x100000001, 0x90
+